In a fuel pressure regulation system of said kind, which is often used in common-rail injection systems, the pressure in the pressure accumulator is regulated in that a closed-loop pressure control circuit is formed in which the first valve is used as a final control element. In this case the second valve serves as a protective pressure relief means. Alternatively the pressure is regulated by means of a closed-loop pressure control circuit in which the second valve is used as a final control element.
However, said two closed-loop control circuits must be coordinated in such a way that only one of the two is active at any given time. This gives rise to difficulties in particular when it comes to the switchover or transition from one closed-loop control circuit to the other.
Which of the two closed-loop control circuits is active is often chosen as a function of the operating point of the internal combustion engine. The inactive closed-loop control circuit is then set to a predetermined value.
This approach requires an initialization of the two control circuits. This is associated with high overhead, for example in terms of implementing the regulation function by programming measures.